Pharmaceutical formulations containing conjugated-estrogens (e.g., Premarin® (conjugated estrogens, USP) made available commercially by Wyeth-Ayerst Laboratories of Philadelphia, Pa.) have long been used for moderate to severe vasomotor symptoms associated with menopause, atrophic vaginitis, osteoporosis, hypoestrogenism due to hypogonadism, castration, or primary ovarian failure, breast cancer in selected persons with metastatic disease, and advanced androgen-dependent carcinoma of the prostate. Premarine® (conjugated estrogens, USP) has been known to contain a mixture of estrogens obtained exclusively from natural sources, occurring as the sodium salts of water-soluble estrogen sulfates blended to represent the average composition of material derived from pregnant mares' urine. As Premarin® (conjugated estrogens, USP) is derived from the urine of pregnant mares, the methods utilized to collect this urine have recently come into question. Animal activists have begun to protest these methods and call for a ban on Premarin® (conjugated estrogens, USP) despite its apparent utility in treating the aforementioned diseases. Premarin® (conjugated estrogens, USP) is generally believed to contain a number of estrogenic compounds. However, despite numerous attempts to characterize Premarin® (conjugated estrogens, USP) over the past several decades, the essential estrogenic compounds present in Premarin® (conjugated estrogens, USP) have remained a mystery.
It would be desirable to obtain a synthetic conjugated estrogens formulation that contains the essential estrogenic compounds present in Premarin® (conjugated estrogens, USP).